It was beautiful. There should be a sequel. I want to delve into the Lolita's mind and see what made her what she is. I mean, an urban legend that kills people yes, but what formed that urban legend. Also the other ones, the dolls that took people's skin and paraded around in them, and the manga artist killer...

Gantz is by far a really scary one if you were to put yourself in the character's shoes, as for H.O.T.D it's not that scary compared to this one, besides both have boobies and such, but Gantz is more serious in a way :d

Uzumaki was creepy but lots of Junji Ito's smaller stories are way more terrifying imo.
The tall lady from Mimi's Ghost Stories gives me the ultimate creeps, the enigma story made me so claustrophobic feeling, the long dream is a terrifying concept, army of one is so uncomfortable, the various monster ladies with creepy eyes and needle teeth.....

Also, Glyceride is the most disgusting story I've ever read, so cringe-wise, that's the winner. Had me gagging at one panel.

Shiki, the only manga that made me freaked out by chapter 6
Higurashi (from Oni to Matsuri) was just epic and gorey!! <3 Kyaa~ Rika-chama
Another -- the anime was freaky, but... manga..not that much
Corpse Party was good...
I think Musume had that weird part where the crossdresser died though, cant remember, but not that scary

Oh, and Ibitsu was pretty chilling. Take into account it was, I COULD say, a retake on Zashiki Onna. Demon, urban legend, horror manga material. The endings of Ibitsu and Uzumaki had me torn.

Never read Gantz. Isn't that where the WHY U NO?! meme came from? I remember reading a few chapters I think. If anything, Gantz can be considered GORE not SCARY. But, I haven't read the manga, so at this point I'm kind of speaking alone.

Any of Junji Itou's works will cripple you for weeks. His shit is fucked up scary. Also look into Furuya Usamaru. Did Litchi Light Club, prequel and sequel, and a manga adaptation of Suicide Girls. Usamaru's more on the gory side though, in my opinion. Junji's shit really gives you nightmares.

Two words: Glyceride, Uzumaki. Try not to puke.

I've heard Higurashi is scary as Hell, but I've never been able to get into it. And for the love of God if there ever was one, Highschool of the Dead is not scary. Fanservice out the ass paired with slicing zombies does NOT make a good horror manga. No, that's what yields something like Lollipop Chainsaw.

I did read into Fuan no Tane. Pretty decent. Not much for urban legends, more of a creepypasta guy. Hell, that's contradictory. I always want to believe that there is a chance that there are evils out there like that in this world we call Earth.

Take what I said about Usamaru back. Just read Plastic Girl, and he is certified for horror.